Delete Many Rows

Hi All,
I am designing a purge process for a db that has grown to almost 200GB.
My purge process will remove about 1/3 of the 500 million rows spread
over seven tables. Currently there are about 35 indexes defined on
those seven tables. My question is will there be a performance gain by
dropping those indexes, doing my purge, and re-creating the indexes. I
am afraid that leaving those indexes in place will create a lot of
extra overhead in my delete statements by having to maintain the
indexes. I know that it could take many hours to rebuild the indexes
afterward, but I am planning on doing that anyway. The reason that I
want to know whether I should drop the indexes ahead of time, is I may
not be able to do the entire purge at once and the tables may need to
be accessed between purges. If this occurs, I will need to have those
indexes in place.

So do I drop the indexes before the purge and re-create them later or
do I leave them in place and re-index them afterward?

Thanks In Advance

p.h.